RequestAttribute (Spring Framework 5.2.12.RELEASE API)

```
@Target(PARAMETER)
@Retention(RUNTIME)
@Documented
public @interface RequestAttribute
```
Annotation to bind a method parameter to a request attribute.
The main motivation is to provide convenient access to request attributes from a controller method with an optional/required check and a cast to the target method parameter type.
从以下版本开始:
4.3
作者:
Rossen Stoyanchev
另请参阅:
RequestMapping, SessionAttribute

- 可选元素概要
  可选元素
  修饰符和类型可选元素说明
  String name
  The name of the request attribute to bind to.
  boolean required
  Whether the request attribute is required.
  String value
  Alias for name().

- 元素详细资料
  - value
```
@AliasFor("name")
String value
```
    Alias for name().
    默认值:
    ""
- - name
```
@AliasFor("value")
String name
```
    The name of the request attribute to bind to.
    The default name is inferred from the method parameter name.
    默认值:
    ""
- - required
```
boolean required
```
    Whether the request attribute is required.
    Defaults to true, leading to an exception being thrown if the attribute is missing. Switch this to false if you prefer a null or Java 8 java.util.Optional if the attribute doesn't exist.
    默认值:
    true